Short fiber composite material

ABSTRACT

A method of forming a fiber reinforced composite material includes cutting a plurality of reinforcing fibers to a selected length, directing the plurality of reinforcing fibers through a fiber alignment mechanism, orienting the plurality of reinforcing fibers in a selected direction via the fiber alignment mechanism, and adhering the aligned plurality of reinforcing fibers to a substrate material to form the fiber reinforced composite material. A system for manufacturing a fiber reinforced composite material includes a feed mechanism to direct a substrate material along a selected path, a cutting mechanism to cut a plurality of reinforcing fibers to a selected length, and a fiber alignment mechanism to orient the plurality of reinforcing fibers in a selected direction before adhering the plurality of reinforcing fibers to the substrate material.

BACKGROUND

The subject matter disclosed herein relates to fiber reinforcedcomposite materials, and more particularly to composite materials havingdiscontinuous fiber reinforcement.

Continuous fibers, such as continuous carbon fibers or continuous glassfibers, are traditionally used as reinforcement for polymer matrixcomposite (PMC) material. Continuous fiber tows, or rovings, are used tomake either prepreg tapes (including the fiber and a matrix materialsuch as epoxy resin) or woven into a fabric. Prepreg tapes withcontinuous fibers are generally not flexible enough to form componentswith complex shapes. Further, the mechanical performance of theuni-directional continuous fiber prepreg materials are superior to wovenfabric reinforced composites due to the fiber undulation necessary toconstruct the woven fabric.

As an alternative to the continuous fiber construction, materials withrelatively short fiber lengths are being produced. One method of suchproduction begins with continuous fibers, which are then stretched untilthe continuous fibers break into shorter fibers. Such a process iscostly, since it uses continuous fibers as its basis. Further, thestretch-break process is difficult to control. Other short fiberproduction technologies exist, but those processes result inrandomly-oriented short fibers, in which the directional or anisotropicadvantages of composite materials are lost.

SUMMARY

In one embodiment, a method of forming a fiber reinforced compositematerial includes cutting a plurality of reinforcing fibers to aselected length, directing the plurality of reinforcing fibers through afiber alignment mechanism, orienting the plurality of reinforcing fibersin a selected direction via the fiber alignment mechanism, and adheringthe aligned plurality of reinforcing fibers to a substrate material toform the fiber reinforced composite material.

Additionally or alternatively, in this or other embodiments the fiberalignment mechanism is one of air, an ultrasonic field or an alignmentblade.

Additionally or alternatively, in this or other embodiments directingthe plurality of reinforcing fibers through the filter alignmentmechanism includes directing the plurality of reinforcing fibers throughan electrical field to orient the plurality of reinforcing fibers in theselected direction.

Additionally or alternatively, in this or other embodiments adhering thealigned plurality of reinforcing fibers to the substrate materialincludes adhering the aligned plurality of reinforcing fibers to amatrix material.

Additionally or alternatively, in this or other embodiments the alignedplurality of reinforcing fibers and the substrate material are directedthrough a consolidation roller to adhere the aligned plurality ofreinforcing fibers to the substrate material.

Additionally or alternatively, in this or other embodiments the fiberreinforced composite material is collected at an output roller.

Additionally or alternatively, in this or other embodiments theplurality of fibers is a plurality of carbon fibers or glass fibers.

In another embodiment, a system for manufacturing a fiber reinforcedcomposite material includes a feed mechanism to direct a substratematerial along a selected path, a cutting mechanism to cut a pluralityof reinforcing fibers to a selected length, and a fiber alignmentmechanism to orient the plurality of reinforcing fibers in a selecteddirection before adhering the plurality of reinforcing fibers to thesubstrate material.

Additionally or alternatively, in this or other embodiments the fiberalignment mechanism is one of an airflow, or an ultrasonic emitter.

Additionally or alternatively, in this or other embodiments the fiberalignment mechanism includes a conductive element configured to emit anelectrical field, the electrical field configured to orient theplurality of reinforcing fibers in a selected direction when theplurality of reinforcing fibers pass through the electrical field.

Additionally or alternatively, in this or other embodiments the fiberalignment mechanism includes an alignment blade to mechanically orientthe plurality of reinforcing fibers in a selected direction.

Additionally or alternatively, in this or other embodiments aconsolidation roller adheres the plurality of reinforcing fibers to thesubstrate material.

BRIEF DESCRIPTION OF THE DRAWINGS

The subject matter is particularly pointed out and distinctly claimed atthe conclusion of the specification. The foregoing and other features,and advantages of the present disclosure are apparent from the followingdetailed description taken in conjunction with the accompanying drawingsin which:

FIG. 1 is a schematic illustration of an embodiment of a fiberreinforced composite material;

FIG. 2 is an illustration of a manufacturing process for a fiberreinforced composite material;

FIG. 3 is an illustration of another embodiment of a manufacturingprocess for a fiber reinforced composite material; and

FIG. 4 is an illustration of yet another embodiment of a manufacturingprocess for a fiber reinforced composite material.

DETAILED DESCRIPTION

The present disclosure includes continuous relatively low-costmanufacturing processes for fabricating short-fiber tapes or prepregmaterials in which the short fibers are aligned in a selected direction.The processes integrate cutting to length, alignment, and impregnationof the aligned fibers into a matrix material sequentially.

Referring now to FIG. 1, shown is a schematic illustration of anembodiment of a fiber reinforced composite material 12. The compositematerial 12 includes a matrix film 14, which in some embodimentsincludes an adhesive material, such as an epoxy adhesive material. Thecomposite material includes a plurality of reinforcing fibers 18, suchas carbon fibers or glass fibers, arrayed in the matrix film 14. Thereinforcing fibers 18 are discontinuous and are aligned and oriented toextend in a selected direction. One skilled in the art will readilyappreciate that other fibers may be utilized in the composite material12.

Referring now to FIG. 2, illustrated is an example of a manufacturingprocess 10 for fabricating the composite material 12 with discontinuousfibers oriented along a selected direction. The process 10 utilizes thematrix film 14, and in some embodiments, the matrix film 14 is providedin roll form for feeding into the manufacturing process 10. Reinforcingfiber material 16, including reinforcing fibers 18, is provided forutilization in the manufacturing process 10.

The matrix film 14 is fed continuously from a feed portion, for example,a feed roller 20 to an output portion, for example, an output roller 22.While the matrix film 14 follows this path from the feed roller 20 tothe output roller 22, the reinforcing fiber material 16 is fed into themanufacturing process 10 over the matrix film 14. The reinforcing fibermaterial 16 may be in the form of, for example, a narrow sheet, a tow orroving, or a yarn. The reinforcing fiber material 16 proceeds through afiber cutter 24 where the reinforcing fiber material 16, and thus thereinforcing fibers 18 in the reinforcing fiber material 16, are cut to aselected fiber length.

The cut reinforcing fibers 18 are then laid on the passing matrix film14. In some embodiments, the fiber cutter 24 is located over the matrixfilm 14, so the cut reinforcing fibers 18 are placed on the matrix film14 via gravity. The matrix film 14 has a selected degree of tackiness orstickiness allowing for movement of the cut reinforcing fibers 18 on thematrix film 14 while maintaining adhesion of the cut reinforcing fibers18 at the matrix film 14. The matrix film 14 and cut reinforcing fibers18 proceed to a fiber orientation mechanism 26. The fiber orientationmechanism 26 acts on the cut reinforcing fibers 18 to move the cutreinforcing fibers 18 to a selected orientation, for example, orientingthe cut reinforcing fibers 18 along a length 28 of the matrix film 14,or conversely, across a width of the matrix film 14. In otherembodiments, the selected orientation may be not along the length 28 oracross the width, but may be at an angle nonparallel to both the widthand the length 28.

The fiber orientation mechanism 26 may utilize one or more technologiesto move the cut reinforcing fibers 18 to the selected location as thecut reinforcing fibers 18 are placed on the matrix film 14, or after thecut reinforcing fibers 18 contact the matrix film 14. Such technologiesmay include, but are not limited to, a flow of air to orient the cutreinforcing fibers 18, dielectrophoresis, where the cut reinforcingfibers 18 are subjected to an uneven electrical field to orient the cutreinforcing fibers 18, or ultrasonic waves may be utilized to align thecut reinforcing fibers 18. In other embodiments, as shown in FIG. 3, aplurality of alignment blades 40, which may be stationary or moving, areused to align and orient the cut reinforcing fibers 18. Once the cutreinforcing fibers 18 are aligned in the selected orientation, thematrix film 14 and cut reinforcing fibers 18 are passed through aconsolidation mechanism, for example, consolidation rollers 30, wherethe cut reinforcing fibers 18 and the matrix film 14 are consolidated toform the composite material 12, in the form of a composite materialtape, which is wound onto the output roller 22.

Another embodiment of the manufacturing process is illustrated in FIG.4. In the embodiment of FIG. 4, instead of collecting the cutreinforcing fibers 18 at the matrix material 14, a paper 32 or othersuch material with a selected degree of adhesion is utilized to collectthe cut reinforcing fibers 18. Once the reinforcing fibers 18 are cut,or alternatively chopped, at the fiber cutter 24, the cut reinforcingfibers 18 pass through the fiber orientation mechanism 26 for alignmentin the selected direction. In the embodiment shown in FIG. 4, the fiberorientation mechanism is an electrical field or voltage potentialapplied at conductive elements 34. A voltage is applied across theconductive elements 34, and the cut reinforcing fibers 18 pass betweenthe conductive elements 34 and are thus subjected to the electricalfield, resulting in the alignment of the cut reinforcing fibers 18 inthe selected direction.

The oriented or aligned cut reinforcing fibers 18 proceed, in someembodiments via gravity, to the paper 32 to which the cut reinforcingfibers 18 are adhered. In some embodiments, the reinforcing fibers 18and paper 32 then may pass through a tackifier, such as a spraytackifier 36 to further adhere the cut reinforcing fibers 18 to thepaper 32, and may proceed through consolidation rollers 30. As needed,the paper 32 may proceed past the fiber cutter 24 more than once tocollect additional cut reinforcing fibers 18. The paper 32 and cutreinforcing fibers 18 can then be fully impregnated with matrix material14 resulting in the composite material 12 with discontinuous reinforcingfibers 18 with an alignment in a selected direction.

The composite material 12 with aligned, discontinuous reinforcing fibers18 may be more readily utilized to fabricate complexly-shaped componentsbecause the discontinuity of the reinforcing fibers 18 increasesflexibility of the composite material 12. Further, because of thealignment of the reinforcing fibers 18, the anisotropic or directionalproperty features of a traditional composite material are maintained.

While the present disclosure has been described in detail in connectionwith only a limited number of embodiments, it should be readilyunderstood that the present disclosure is not limited to such disclosedembodiments. Rather, the present disclosure can be modified toincorporate any number of variations, alterations, substitutions orequivalent arrangements not heretofore described, but which arecommensurate in spirit and/or scope. Additionally, while variousembodiments have been described, it is to be understood that aspects ofthe present disclosure may include only some of the describedembodiments. Accordingly, the present disclosure is not to be seen aslimited by the foregoing description, but is only limited by the scopeof the appended claims.

What is claimed is:
 1. A method of forming a fiber reinforced compositematerial comprising: cutting a plurality of reinforcing fibers to aselected length; directionally orienting a plurality of along a selectedorientation through a fiber alignment mechanism; and adhering theplurality of reinforcing fibers to a substrate material to form thefiber reinforced composite material.
 2. The method of claim 1, whereinthe fiber alignment mechanism uses one of air, an ultrasonic field or analignment blade.
 3. The method of claim 1, wherein directing theplurality of reinforcing fibers through the filter alignment mechanismcomprises directing the plurality of reinforcing fibers through anelectrical field to orient the plurality of reinforcing fibers in theselected direction.
 4. The method of claim 1, wherein adhering thealigned plurality of reinforcing fibers to the substrate materialcomprises adhering the aligned plurality of reinforcing fibers to amatrix material.
 5. The method of claim 1, further comprising directingthe aligned plurality of reinforcing fibers and the substrate materialthrough a consolidation roller to adhere the plurality of reinforcingfibers to the substrate material.
 6. The method of claim 1, furthercomprising collecting the fiber reinforced composite material at anoutput roller.
 7. The method of claim 1, wherein the plurality of fibersis a plurality of carbon fibers or glass fibers.
 8. A system formanufacturing a fiber reinforced composite material, comprising: a feedmechanism to direct a substrate material along a selected path; acutting mechanism to cut a plurality of reinforcing fibers to a selectedlength; and a fiber alignment mechanism to orient the plurality ofreinforcing fibers in a selected orientation before adhering a pluralityof the plurality of reinforcing fibers to the substrate material.
 9. Thesystem of claim 8, wherein the fiber alignment mechanism is one of anairflow, or an ultrasonic emitter.
 10. The system of claim 8, whereinthe fiber alignment mechanism includes a conductive element configuredto emit an electrical field, the electrical field configured to orientthe plurality of reinforcing fibers in a selected direction when theplurality of reinforcing fibers pass through the electrical field. 11.The system of claim 8, wherein the fiber alignment mechanism includes analignment blade to mechanically orient the plurality of reinforcingfibers in a selected direction.
 12. The system of claim 8, furthercomprising a consolidation roller to adhere the plurality of reinforcingfibers to the substrate material.